“First and foremost, our hearts go out to the family, friends and co-workers of the construction worker who was killed in this tragic incident, and our thoughts remain with the two other workers who were injured this morning and their loved ones,” the university said in a brief statement.

The building was being taken down to make way for a public plaza that is part of the university’s second phase, which remains years away. The scheduling of the construction work was not immediately clear—why demolish now to leave vacant for later.

A Columbia spokesperson declined to discuss the circumstance of the accident and whether the university shared any of the blame for what happened, though in the past a strict safety regimen at the site has been touted. The Department of Buildings said that its initial investigation determined that a structural beam had been cut, for reasons that remain unclear, which caused the rest of the building to come down around three construction workers who were trapped inside. Two of them survived.

Columbia directed further comment to Land Lease, the international general contractor overseeing the demolition work. The firm hired Breeze International of Brooklyn to perform the job. Breeze had received two stop work orders on the project from the Department of Buildings for failure to notify the city that the work had commenced, but those violations were rectified shortly thereafter and the work resume.

Land Lease released a statement that recounted the details of the accident, noting that the building was between 80 and 100 years old and that Breeze had a full-time safety inspector on duty when the accident took place around 8 a.m. “We are working with Breeze, DOB and the BEST squad to determine how this incident occurred,” the statement concluded, referring to the Department of Building’s Building Enforcement Safety Team. “Our thoughts and prayers are with the deceased worker’s family and the family of the injured along with all workers on site this morning.”

This is not the first accident at the 17-acre Manhattanville site. Two years ago, a worker suffered a heart attack and fell down an elevator shaft during a different demolition project. Contractors promised to increase safety at the site following the incident, and workers said they were satisfied with the changes. That project was also handled by Breeze International.